The Scottish Liberal Democrats would support a boycott of controversial tests for primary one pupils, the party’s leader will tell members.

Willie Rennie will use his speech at the Lib Dem autumn conference to attack the Scottish nationalstandardised assessments, which have been criticised by teachers.

He will also call for “formal” education to start when children are aged six or seven – a move being explored by Scotland’s largest teaching union – as he addresses delegates at the one-day event in Dunfermline.

The Lib Dems will “stand with” parents and school staff if they snub the literacy and numeracy tests, aimed at helping teachers judge progress on a child’s learning, Mr Rennie will say.

Willie Rennie has said the tests have led to a ‘tidal wave of concern’ from teachers (Jane Barlow/PA)

Education Secretary John Swinney announced changes to assessments last month after hearing feedback from parents, staff and unions.

He said that while there is no statutory right for parents to withdraw their child from any aspect of schooling, they could discuss participation in the tests with their school.

Opposition parties called for the P1 assessments to be scrapped altogether.

Mr Rennie will say: “International evidence shows that the under-sevens need a play-based approach to learning with plenty of opportunities for active, outdoor, social, self-directed play.

“One teacher in Aberdeen said she had never seen such ‘cruel nonsense’ in all of her life, branding the tests ‘a shambles’.

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“Another said ‘this is a massive use of staff resources that could be put into supporting children instead’.

“And to cap it all, an East Ayrshire teacher said the information gathered was ‘completely useless’.”

Mr Rennie said ministers had failed to listen to concerns when they were first raised, and warned the Scottish Parliament’s opposition parties would defeat the minority Government in a vote against the tests.

“At that point if the pupils, parents and teachers boycott these tests, we will stand with them,” he will add.

“These tests are damaging and they’ve got to go.”

On reforms to primary education, he will add: “I want schools be able to change the way we teach children aged four and five.

“We should start formal schooling at six or even seven.

“I want children in Scotland to get the long-term educational benefits. Because education is on the wrong track.

“So today I am committing to work with the education charity Upstart to develop a full programme for change.”

Commenting on the proposal, a spokeswoman for the teaching union, the Educational Institute of Scotland, said: “The EIS AGM agreed last year to investigate the opportunities and challenges associated with a change to the school starting age through a possible move to a kindergarten model of early years education.

“This work is ongoing, and we will be seeking the views of our members in early years and primary establishments as part of this process.”

On Mr Rennie’s support for a boycott, a spokesman for Mr Swinney said: “This is deeply irresponsible from Willie Rennie.

“For the sake of a cheap party conference speech line, he wants to threaten the future of children’s education. That is reprehensible, even for the Lib Dems.”

“School assessments have been used in Scotland for years.

“Throughout that time we didn’t hear a peep from Willie Rennie. It would appear he only discovered he was against school assessments when a new version was introduced by the SNP government.”